FEMALE ORGANS OP GENERATION. 189 



than their mere passage, for the impregnation of the egg, as we shall 

 see below ( 208), does not take place here, but probably at the end 

 of the egg-tube, at least its development commences there. In those 

 instances only in which this portion of the female organs is provided 

 with appendages which secrete a gluten do the eggs remain somewhat 

 lonsrer in this common duct to be covered by the secretion of those 



O * 



glands, that they may be thereby fixed as with a gum to the leaves of 

 plants and other objects. Consequently this portion of the sexual 

 organ is nothing more than a canal, and we must ascribe as well 

 to insects as to many other inferior animals a uterus bicornis ; 

 indeed in the majority of cases, particularly those which possess ovaries 

 having many egg-tubes, a uterus multicornis, for at the end of the egg- 

 tube the development of the egg commences, and here consequently also 

 its impregnation by the semen ensues. 



140. 



APPENDAGES TO THE EGG-CANAL. 



The egg-duct is most rarely a simple organ unprovided with vesicular 

 or vascular auxiliary cavities, as, for example, in Donacia, Erisialis 

 tenax, Musca, Tipula, Ephemera (PI. XXVII. f. 13) ; in the majority 

 of insects, on the contrary, it exhibits various appendages which take a 

 variety of forms, and exercise different functions. 



These appendages vary in number from one to five. If one only be 

 present it is always a vesicular or purse-shaped distension of the duct, 

 which appears destined to the reception of the male semen during copu- 

 lation, and is thence called the SPERMATHECA. This organ is always- 

 situated at the superior parietes of the duct, and opens into it with a 

 small orifice surrounded by a callous margin. This margin is properly 

 the sphincter of the neck of the bag, which prevents the escape of the 

 semen. When it opens the semen flows immediately into the duct 

 from the mere situation of the bag. According to Audouin, the male 

 organ during copulation passes into the orifice of this bag, and thus 

 pours the semen directly into this receptacle. We find this kind of 

 simple vesicular appendage in Acheta, Blatta, Anthidium (PI. XXVII. 

 f. 14.), Ascalaphus, Sialis, Semblis, Psocus, and Nepa ; the same in 

 Hydrophilus, Tenebrio, Lytta, and Chrysis, but in the latter it has a 

 superior or lateral vascular apex (PI. XXVII. f. 15.), which is evi- 

 dently the organ we shall presently describe as the gluten gland. In 

 general, namely, this vessel discharges itself into the duct contiguously 



